Brachydactyly is a genetic disease in which the middle phalanx of the fingers is missing. It is caused by being heterozygous for a certain gene. Homozygotes for that gene are born with severe skeletal malformations and do not survive.

Brachydactyly Type A1

Abnormal shortness of the fingers and toes. Inheritad as an autosomal dominant trait. Symptoms: extra carpals, short phalanges, short thumbs, short metacarpals, syphalangism of the fingers and 2nd and 3rd toes, short femurs, and sometimes ansent phalanges. Fatal during infancy because of major skeletal defects.